Manufacture of cements



Dec. 1Q, 1929.

A. BAUCHERE r AL MANUFACTURE or cm a Sheets-Sheet s out. I The kilnemployed for this purpose may Patented Dec. 10, 1929 PATENT OFFICEANTOINE BAUGHERE AND GABRIEL ARNOU,

OF PARIS, FRANCE MANUFACTURE OF CEMENTS Application filed November 10,1924,

This invention relates to themanufacture of fused cement.

It is already generally known that the whole series of artificialcements can be obtained by. fusion. 1

Those cements, however, the fus on point of whichis very high can-beobtained only by means of an electric furnace, but as regards the othersthe ordinary kilns used in the industry maybe employed by adoptingspecial arrangements.

The object of this invention is to provide means in an apparatusintended for themanufacture of fused cement wherein the oper-' ation offusion is effected in two periods and in two separate kilns, forpreventing access of the high heat of the fusing kiln to the preparatorykiln, and thus avoiding fusing art of the materials in the preparatorykiln, which ordinarily causes the formation of an obstructing ring orelevation of material in the partially fused or pasty state, betweenthetwo kilns. I

In the first period the material-is prepared.

The kiln employed for this purpose is generally a rotaiyk'ln of whichthe temperature may be regulated atwill for the operation to be effectedtherein.

In the second period the fusion is carried be a rotary kiln, a fixedcylindrical kiln, a reverberatory kiln or generally any suitable kiln orfusion apparatus.

The apparatus of the present invention must allow of:

(1) Operation under low pressure in the preparatory kiln and underpressure in the fusion kiln, whichis relatively higher than in thepreparatory kiln.

(2) The temperature control of the products of combustion passing fromthe fusion kiln before their entrance intothe preparatory kiln.

(3) The prevention of the gases of the fusion kiln from entering-thepreparatory kiln by the same opening as serves for the passage of thematerial from the preparatory kiln into the fusion kiln.

Serial No.7 18,993, and in France December 4, 1923.

This latter condition is essential for venting stoppages andobstructions.

This may be done more particularly by surrounding the conduit throughwhich the material passes with taining compressed air. This air isintroduced into the conduit through suitable openings in downwardlyconvergent jets so as to completely prevent the passage of the gasprefrom the fusion kiln into the preparatory kiln.

Theinvention will now be more particular- 1y described with reference tothe accompanying drawings, in which three arrangements and in which:

Figures 1 and 2 are views in longitudinal and transverse sectionalelevation of a rotary preparatory kiln sion kiln Figure 3 is a detail onan enlarged scale of a feed for the injection of compressed air.

Figure 4 illustrates in vertical section a rotary preparatory kilncombined with a fixed cylindrical fusion kiln. (drawn for conveniencesake at right angles to the preparatory kiln).

Figure 5 shows in longitudinal section a rotary preparatory kilncombined with a reverberatory fusion kiln.

Referring to these drawings:

PP. represents the preparatory kiln,

FF the fusion kiln,

T the pipe for the passage of materials from the preparatory to thefusion kiln.

N the ring containing compressed air which when forced into the pipe Tprevents gas from passing from the fusion kiln into the, preparatorykiln by this pipe.

S the pipe allowing the fusion kiln into the preparatory kiln.

V an aperture for the air which cools the gases coming from the fusionkiln and entering the preparatory kiln.

Y valve or damper enabling the fusion kiln 95 a-circular pipe con- 55hereinbefore mentioned are illustrated,

combined with a rotary futhe passage of gas from ments the passage ofthe products of combustion from the fusion kiln into the preparatorykiln takes place by means of a pipe independent of the one through Whichthe materials treated pass from the preparatory kiln into the fusionkiln.

By this means fusion of the materials treated, before their arrival inthe fusion kiln, is prevented.

It must'be noted that the present invention is not limited merely to theforms of construction illustrated in the accompanying drawings but thatit covers all the modifications wherein the pipe carrying the gases fromthe fusion kiln into the preparatory kiln is independent of the one bywhich the material travels in the opposite direction. Thus for example,the compressed air injection ring may be replaced by any other suitableair injection apparatus and the pressure in the fusion kiln and thecooling of the fumes between the two kilns may be obtained by any othersuitable means than by the dampers and by the admission of cold airrespectively.

Having now particularly described and ascertained the nature of our saidinvention and in what manner the same is to be performed, we declarethat what we claim is:

1. Apparatus for the production of fused cement comprising an inclinedrotary preheating furnace and fusion furnace,- means for heating saidfusion furnace to a temperature above the fusion point of the cementmaterials, a conduit for passing the solid materials from the preheatingfurnace to the fusion furnace and means associated with said conduit toprevent the escape of gases of combustion from said fusion furnace tosaid conduit, said associated means comprising a supply of fluid underpressure arranged and adapted for discharging said fluid into the saidconduit in the general direction of flow of the cement materials.

2. Apparatus as claimed in claim 1 the fluid under pressure being air.

3. Apparatus as-c1aimed in claim 1 the fluid being at a sufliciently lowtemperature to maintain the materials below their point of fusion duringall of the duration of their passage through said conduit.

In testimony whereof We have signed our names to this specification.

ANTOINE BAUCHERE. GABRIEL ARNOU.

